Automatic oven lighter for gas stoves



July 2o, 1937.l P. L HOLLMAN 2,081,433

AUTOMATIC OVEN LIGHTER FOR GAS STOVES y I Filed Nov. 1, 1932 2 sheets-sheet 1 July 20, 1937. P. l. HoLLMAN 2,087,433

AUTOMATIC OVEN LIGHTER FOR GAS STOVES Filed NOV. l, 1932 2 Sheets-Sheet 2 Patented July 20, 1937 UNITED STATES AUTOMATIC OVEN LIGHTER FOR GAS STOVES Peter I. Hallman, Rockford, Ill., assignor, by mesne assignments, to Reconstruction Finance Corporation, Chicago, Ill., a corporation of the United States Application November 1, 1932, Serial No. 640,695'

' 1 claim. (o1. `15s-,115)

This invention relates to ignitiondevices, and more particularly an automatic oven lighter for gas stoves, and is animprovement on that disclosed in the copending application of Frank A.

Gauger, Serial No. 608,713, led May 2, 1932.

Gas ranges of the more recent designs hat.x low ovens in which the oven burner is disposed at an appreciable distance below the cooking top, and, hence, considerably below the constantly burning pilot light serving as the igniter for the oven burner, as f well .as .for the cooking top burners. It has, therefore, been quite a problem to devise a practical form of flash-back tube to secure quick and positive automatic lighting,

despite the remoteness of the pilot light with respect to the burner, and the fact that the pilot light is so far above the burner. Successful functioning of a long range flash-back tube has been found to. depend primarily on maintaining the right proportion of gas to air, not allowing too much secondary air to mix with the gas admitted to the tube by the auxiliary pilot. The principal object of my invention is to provide a flash-back tube and auxiliary pilot housing cony structed so as to secure such a balanced mixture not only in lighting when the parts are cold, but in re-lighting when the parts are heated, whereby to secure good llame propagation from the main pilot back to the auxiliary pilot.

A special feature of the present invention is the provision of a flash-back tube of a certain sized cross-section, and an Vauxiliary pilot h ousing of larger cross-section and elongated sufficiently to accommodate a rather large jetthe main jet of the auxiliary burner, for charging the flash-back tube.

Another feature is the provision of a secondary air injector between the auxiliary pilot housing and the flash-back tube for the purpose of entraining cold air and accordingly moderating the draft effect in the tube by preventing overheating of the latter.

. The invention is hereinafter fully described by reference to the accompanying drawings, where- Figure 1-is a view partly in elevation and partly in vertical section through a gas range equipped with an oven lighter made in accordance with my Fig. 4 is a fragmentary section similar to Fig. 2

of atmodiiied construction.

Similar reference numerals are applied to corresponding parts throughout the views.

3o Referring to Figs. 1, 2 .and 3, the stove illustrated is of alow oven type, calledv a table-top range, having the usual cooking top` I2 next Vto the loven section I3. The cooking top and the top of the oven section, it will be observed,

are substantially at the same level, about table height. This vaccounts for the low elevation of the oven burner appearingat I4 with respect to the pilot light casing I5 of the automatic lighter I6 disposed in,l the center of the cooking top between theburrners II. They lighter I6 is of a well known type having ashback tubes I8 radiatingtherefrom to conduct gas issuing from a porton any one of the cooking top burners to the lighter for ignition by the flame of the pilot burner I9 in the casing I5. The burner I9, for

`the sake of convenience, will hereinafter be rethrough anv oven regulator 24 connected in anyy usual Way between the oven cock and the pipe 25 extending down toward the mixer 26 of the oven burner. A tube 30 supplied with gas whenever the oven cock is opened serves to supply gas to a second pilot burner 3I.`for igniting the `oven burner. The burner 3|, for the sake of convenience and in order to distinguish from the main pilot I9, willbe referred to hereinafter as the auxiliary pilot. Itis also sometimes referred to as an intermediate burner for the reason that it is` arranged to be automatically `ignited similarly as one of the cooking top burners I'I, and is,arranged to light the oven burner. In other words, the oven burner is not ignited by direct flash-*back thereto through a tube like one of lthe cooking top burners, but relies for its ignition upon the auxiliary pilot between the lighter I6 and the oven burner. The present invention has particularv reference to the flashback tube 32 and auxiliary pilot housing 33 disposed between the main pilot I9 and the auxiliary pilot 3|, arranged to secure ignition of the latter from the former by ilame propagation or flashback through the tube.

The ovenburner I4 has alug 34 projecting therefrom provided with a vprojection 35 by means of` which the same is arranged to be pinned in a slot 36 in a casting 31 fastened as at 38 to the -wall of the oven. The casting 31 serves as a canopy or shield for the auxiliary pilot 3|, which, as shown, projects through an opening in the oven wall and into the casting so that the inner end is disposed in close proximity to the bottom of the oven burner for good lightf ing. The auxiliary pilot 3| has a pad portion 39 provided thereon for abutment with the out-v the same wall, as appears in Fig. 2. The interlocking of the oven burner I4 with the casting 31 and the fastening of the auxiliary pilot 3l `to the j casting in the manner described, positively insures the proper relationship between the auxiliary pilot and the oven burner for good lighting. A mixer 4l is provided on the auxiliary pilot through which gas is delivered under pressure from the tube 30, whereby to produce a Bunsen flame at the row of ports 42 provided in equally spaced relation lengthwise of the top of the auxiliary pilot burner. The ports 42 are all of a small sizev and spaced properly for good llame propagation from the outer end of the burner to the inner end. At the outer end a` large port 43 is provided centrallyy of the bottom of an upwardly projecting neck 44 cast integral with the burner. Openings 45 are provided in the side walls of the collar for good aeration of the jet at the port 43. A largeopening 431s provided in the wall of the neck 44 on'the inner lside thereofl for the purpose of propagating flame from the port 43 to the ports 42, certain ports 41 atzthe outer end of the burner being advantageously located and inclined both for good llame propaga-,- tion and to insure good heating of a bimetallic thermostat 43, which controls the opening and` f closing of a shut-off valve, not shown, interposed between the supply'pipe 26 and the mixer 23 of the oven burner.

The large main port 43 in the louter end of the auxiliary pilot burner 3lis the means for charging the flashback tube 32, and it is at this point that the auxiliary pilot is ignited when the flashback occurs. I have found through experimenting that the quickest and most positive lighting depends upon a good flow ofgas from this port. which naturally necessitates enlargement thereof with relation to the size ofthe ports that are only to serve for chain lighting from one yend of the burner toV the other. I have also found that the enlargement of the main port should be tt e certain extent proportionate to the remoteness the main pilot I3. The jet at this" port will accordingly be quite large, and that accounts for the size of the housing 33 which, as shown, has the base portion 50 thereof fitting on the reduced upper end 5I of the collar 44. I 'prefer to have the housing 33 large enough in diameter and long enough so that the jet doesnotcome into contact with the walls of the housing.` In that way there is no likelihood of any objectionable odor in operation. The flash-back tube 32 is smaller 'in diameter thanthe housing 33, and has its lower end fitting ina. neck 52 provided on the upper end of the housing. A bell-shaped enlarged kportion 53 is formed on the upper end of the housing directly under the neck 52 and has a series of holes 54 opening into the bottom thereof around the outside of the upper end of the housing, whereby to form an injector to entrain airwith the products of combustion from the main jet and accordingly moderate the heating of the flash-back tube 32 so that there will be no excessive draft. Such heating as the tube 32 may be subjected'to while the main jet is hurr'iirig.V is also' bound to be `dissipated soon after the'auxiliary pilot burner is extinguished, owing to the circulation of cold air through the tube 32 taken in through the holes by reason of the draft effect in the tube. Consequently, there will beno difliculty in relighting the oven burner should the housewife want to do so soon after the oven burner has been turned od'. The tube 32 has its upper end fitting in a neck Il von theside of the housing il of the lighter I3, so that the combustible mixture discharged into the lower end of the tube from the port 43 is conducted through the tube to the main pilot I3 for vignition.1whereuponv a dash-back occurs through the tube to ignite the auxiliary pilot 3i, ilrst at' 'the port 43 and then by flame propagation to the ports 41 andports 43. The tube 32 has one side wall thereof cut at points uniformly spaced lengthwise of the vertical portion of the tube, as appears at I3, a portion of the wall below each cut being pressed in or indented whereby to provide atmospheric openings l1. This is to.

auxiliary pilot and the air mixed therewith in the tube to secure immediate dash-back from the' main pilot to the auxiliary pilot. The construe. tion illustrated and just described has been found to give very good results with natural gas. which is admittedly the most dimcult to handle so far as automatic flash-back lighting is concerned. Where manufactured gas is to be used. the housing for the main jet may take the form illustrated at 33' in Fig. 4. It willbe observed that this housing has no injector at the upper end thereof but is made simply large enough and longenough to accommodate the jet.' I have found that regardless of the fact that the draft isnot checked and najspecial effort is made to cool of! the nashback tube. there is no dimculty in reiighting with manufactured gas. f

It should bev understood that while housings 33 and 33' are shown as separate cast parts. these may be formed lin one piece with the tubes, simply `-by enlargement of the end of the tube -in a manner. thought to be self-evident. and the It is believed the foregoing description `conveys a good understanding of the objects and advan.- tages of my invention. The appended claim his been drawn with a view to coveringall legitimate modifications and adai'itatlons.'vv

I claim:

In combination, a ilrst gas burner', a second gas burner to be ignited from the first burner and located at a lower elevation,l a *flash-back tube `disposed with its lower end adjacent thesecond burner and its upper end adjacent the first burner, the second burne'rhaving anenlarged port arranged to discharge'gas intothe lush-hackl tube, a substantially vertical housing of cross-section .relative tothe cross-section of the l p flash-back tube'disposed overlaid port and comings provided in the bottom thereof.

1 rivm r. Houma.

appended claim should be construed accordingly.

IiiV 

